Qmatic & HS Top Speed?

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Dbogue

New Member
Mar 7, 2012
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I'm looking into purchasing the Qmatic and am wondering what kind of setup will give me the highest top speed. My stock HS will get me up around 32-33 with a little shove to get going. Not great bottom end but I never have to peddle. I'm basically looking for the same thing from the Qmatic. A little shove to get going and higher top speed. I can't imagine that I'm the only one wondering about the speed gains possible from the adjustability and efficiency of the Qmatic. Does anyone have that type of info? Say with a 56t rear sprocket and 26x2.125 wheels/tires, what's the top speed a 175lb rider could get with a HS and minimal peddling (theoretical or real-world)?
Also, I've read that the Qmatic should be paired with at least a 56t but can you go any lower? Would you get any real speed increases or would it be too hard on the gearbox?
I've done some theoretical calculations with agk's calculator and it says I should be able to hit 56mph xct2 LOL! Needless to say, I neither have the know-how nor the information to compute what I'm looking for. Does anyone else?
 

azbill

Active Member
May 18, 2008
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with a 56, you should be able to cruise in the mid to high 30's easily
with a 72, I was cruising @ 27-29 ;)
(and could do it till my butt got sore from riding) laff

top end should be 40+
 

Dbogue

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Mar 7, 2012
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I currently run a 40t with the pirate (manic mechanic) hub adapter. What would happen if I ran it on the qmatic instead of buying a 56t for it?
 

The_Aleman

Active Member
Jul 31, 2008
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el People's Republik de Kalifornistan
Well, you can only go so fast with the amount of power you have. 2HP gets you 36-42 MPH depending on wind, from my experience.

A Q-matic with 56T is plenty capable of that. With a 40T, your top speed won't go up much, if at all, and you'll be struggling on take-off and hills.
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
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Ridin' inSane Diego, CA.
As Aleman said.......I run no smaller than a 56t on my Q-matic and I've tried all gearing combinations. The 56t is where it's at on this set-up. If you climb big hills I would advise going larger as azbill has done.....72t or so.

dnut

Well, you can only go so fast with the amount of power you have. 2HP gets you 36-42 MPH depending on wind, from my experience.

A Q-matic with 56T is plenty capable of that. With a 40T, your top speed won't go up much, if at all, and you'll be struggling on take-off and hills.
 

Dbogue

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Mar 7, 2012
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I don't have any major hills in my daily commute. Thanks for testing out the different combos so guys like me can be well informed :) looks like a 56t is in my future..
 

Dbogue

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Mar 7, 2012
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Ya, I don't peddle at all with my current 40t setup. What kind of gearing are you running with your 99cc?

What's the jack shaft setup? Is it a gearbox replacement? How does it give you both better low and top end? .wee.
 

Mightyboosh

New Member
Apr 28, 2012
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College Station, TX
I thought the jack shaft system just let you center the engine on the frame. i looked at one, i think it was at affordablegokartsupply.com. it looked like one gear had a more theeth then the other but it didnt say anything about that in the specs.
 

GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
A jack shaft system can be used for multiple needs.
1. Allows further reduction in gearing.
2. Allows many different choices in overall gearing.
3. Allows a builder to run both a chain and a belt in the drive system if one so chooses to do so.
4. Allows a builder to offset the rear drive chain or belt to accommodate any rear tire width (the most common limiting factor would be rubbing on the chain or seat stays).
This also allows for easier, (than some kits) proper chain/ belt alignment.
5. Allows reversal of direction of rotation for some engine/ transmission combinations that turn the wrong way.

I hope that this clears up at least some of the confusion.
 

Sidewinder Jerry

Well-Known Member
Dec 19, 2011
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Rockwood, TN
You can see mine by viewing my album. Just click on my name. The engine drive system runs to your crank instead of the rear wheel. I use a Staton Inc crank drive this way my bike can use 21 gears to propell itself.
 

Dbogue

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Mar 7, 2012
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I don't like to pedal at all, so for me the 64 tooth & H.S. was just right. Now I'm running it with the 99cc Predator and Q matic... sweet.
SB
That sounds like what I might be toying with in the future. What's the setup that you run with the extra power you get from the preddy?
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
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northeastern Minnesota
All I did was swap out the motor with the HS. I did have to alter the mounts some to make the stock mounts work and I had to redrill the mounting holes in the transmission backing plate. A different pulley and belt ( I can look that up) and I'm using the same 64 tooth driven sprocket. I also made up my own exhaust manifold and then made an exhaust pipe out of conduit. Lots more power.
SB